Refrigerating system



Feb. 5, 1935. 1.. u. LARKIN 1,990,290

REFRIGERATING SYSTEM Filed Sept. 20, 1952 2 Sheet-Sheet 1 LESTER LARK/NPatented Feb. 1935.-

UNITED: STATES;

1,990,290 REFRIGERATING SYSTEM Lester U. Larkin, Atlanta, Ga., assig'norto Larkin Refrigerating Corporation, Atlanta, (3a., a corporation ofGeorgia Application September 20, 1932, Serial No. 634,049

3 Claims.

The invention forming the subject matter of this application is arefrigeration liquid control system in which a single compressor is usedto supply refrigerating liquid to evaporating coils 5 or units in aplurality of refrigerator showcases or boxes.

The main object of the invention is to provide a system of thischaracter in which the motor operating the compressor isthermostatically controlled so as to operate constantly whenthetemperature in any or all of the boxes exceeds a pr determined maximum;and in which the operation of the motor will be stopped only when thetemperature in all of the boxes falls below the predetermined maximum.

Another object of the invention is to provide in each control unit anelectromagnetically operated valve to stop the circulation ofrefrigerant liquid through any of the boxes in which the temperature hasfallen below a predetermined temperature selected as a maximum for thatparticular box. Y

Qther objects of the invention will become apparent as the detaileddescription thereof proceeds.

In the drawings:

Figure 1 is a diagrammatic layout of the in-' vention as applied to ashowcases or boxes;

Figure 2 is a horizontal section taken on the irregular line 2-2 ofFigure 3; and V Figure 3 is a central vertical section taken on the line33 of Figure 2. As shown in Figure 1 of the drawings, the inventionincludes 'a compressor C of any well known construction. The electricmotor 1 of the compressor is. operated from the mains 2 and 3 through arelay'switch designated generally by the reference character S. Thisrelay switch S comprises a conducting rod 4 mounted to swing about apivot 5 electrically connected by a wire plurality of refrigerating 6 tothe main 2. The rod 4 is normally held out of operativeposition againsta stop 7 by means of a tension spring 8 having one end secured to therod 4 and its other end secured to a suitable fixed part 9.

The rod 4 closes the circuit from the mains 2 and 3 through the motor 1when it is drawn over from the stop 7 into contact with a contact 10connected by wire 11 to one of the terminals 12 of the motor 1. Thereturn from the motor 12 is effected by a wire 13 connecting the otherterminal 14 of the motor to the ground wire 3. The rod 4 is operated bythe energization of an electromagnet 15 having one of its terminalsconnected by a wire 16 to return wire 3. The other terminal of theelectromagnet 15 is connected by a wire 1''! to wires 18 and 19 leadingto contacts 20 and 21, respectively, arranged in the path of movement ofcontacts 22 and 23' of 3-contact mercury bulb switches S1 and S-2 in theboxes B1 and 13-2, respectively. The main 2 is connected by wires 24 and25 through pigtails 26 and 27,-respectively, to the center contactelements of the switches S1 and 8-2, respectively.

The remaining contact 28 of the switch S1 is adapted to swing against acontact 29 at one end of the line 30, having its other end connected tothe terminal 31 ofa solenoid switch 32.

.at one of its ends to the terminal 41 of the solenoid switch 37 and atits other end to the wire 3.v

Since the electromagnetically operated switches are the same in all thecontrol units, it will be suflicient to describe switch 32 in detail. Asshown in Figures 2 and 3, the switch 32 comprises a base plate 42,having a casing 43 suitably secured thereto by means of the machinescrews 44. The casing 43 is shaped to form with the base 42 a closedchamber 45, in which a lever 46 is mounted to rock about a fulcrum pivot47 suitably fixed in standards 48 and 49 (see Figure 2) extending upfrom the base 42.

The short arm of the lever 46 is provided at its end with a notch 50,the opposite walls of which engage the opposite sides of the head 51 ofa needle valve 52 mounted for reciprocation in; a casing 53. The base 42has a bore 54, and the base is drilled from opposite sides to provide thcountersinks 55 and 56.

The countersink 55 forms a seat for the cylindrical casing 53; and thecountersink 56 is tapped to receive the screwthreads of a refrigerantliquid outlet connection 57. The valve casing 53 is provided between itsends with a partition 58 centrally bored to form a passageway 59 adaptedto be closed by the conical end 60 of the valve 52. As usual in devicesof this kind, the body of the valve 52 is polygonal in cross section inorder to permit liquid to flow freely from the chamber 45 to the conicalend 60 of the valve.

The other end of the lever 46 is pivotally connected to the bifurcatedlower end 61 of a rod 62 having a cylindrical head 63 at its upper end.The head 63 slides freely in' the cylindrical bore 64 of an invertedcup-like armature 65 which is slidably mounted in a cylindrical recess66 formed in the top casing 43. A spring 6'7 surrounds the rod- 62 andhas its opposite ends in contact with the head 63 and a split ringwasher 68 suitably The remaining contact 33 of the switch 8-2 is securedin a groove 69 formed in the wall of the bore 64.

The extension 70 of the top of casing 43 is with the bore 54, to receivethe externally screwthreaded end of an inlet fitting '75 having a bore'76 countersunk to receive a screen 77 suitably secured therein by anysuitable friction ring 77.

An elbow fitting '78 screwthreaded into a boss 79 projecting laterallyfrom the cap '72, receives the wires 30 and 38 connecting the solenoidterminals 30 and 39 to the contact 29 and main 3, respectively.

The mercury switch Sl is rocked about a fixed pivot 80 by means of alink 81, having its upper end pivoted to the bracket 82 in which thebulb 83 is mounted.- The lower end of link 81 is pivoted to rod 84 nearone end thereof. The other end of the rod 84 is bevelled to a knife-edge85 which is seated in a notch 86 formed in a fixed member 87. The otherend of rod 84 is pivoted to a loop formed inone end of a compressionspring 88, the other end of which is suitably secured to the end wall 89of a casing 90 in which the switch mechanism is mounted. A secondcompression spring 91 has its upper end suitably fixed to the top 92 ofthe casing 90; and has its lower end pressing against the rod betweenthe ends thereof.

Directly below the axis of spring 91, the rod 84 is supported by thepointed .end 93 of a rod 94 secured to the diaphragm 95 forming theflexible head of a gas filled casing 96. The bottom wall of casing 96 isconnected to a tube'97 leading to a capillary bulb (not shown) clampedto the outlet pipe of the refrigerating coil in the box B-1. The detailsof this thermostatic control form no part of the present invention, asthey are well known in this art.

The spring 88 is mounted so as to give a snapover action to themovements of the rod 84, and to hold the rod 84 steady in either raisedor lowered positions, The spring 91-forms a yielding cushion stop forthe movement of the rod 84 in one direction; while the diaphragmsupported rod 94 forms a yielding support for rod 84 in the oppositedirection.

In Figure 1 of the drawings, the elements of the switch S-1 are shown inthe box 3-1 in the position they occupy when the temperature in box 3-1is at or below the predetermined maximum. In this position, the circuitthrough the starting motor relay 15 is broken by the separation of thecontacts 20 and 22. At the same time, the circuit through thesolenoid-71 is closed by contacts 28 and 29. The closing of thissolenoid circuit raises the armature 65 to pull up the long arm of lever46 (see Figure 3) thereby moving the needle valve 52 into closingposition. This, of course, stops circulation of refrigerant liquidthrough the cooling coils of box B--1.

In box B'2, the mercury switch S-2 is illustrated'in the oppositeposition to that of S1.

The circuit through the motro relay 15 is closed by engagement ofcontacts 23 and 21; and is broken through the solenoid switch 37 byseparation of contacts 33 and 34. The motor 1 therefore remains inoperation to force refrigerant through the solenoid switch chamber andthe cooling unit connected thereto in the box B2. 1

It is immaterial how many cooling units are connected to the compressorcondenser source of off circulation of refrigerant through all of thecooling units.

It will be apparent that the stopping of circulation through units notrequiring it, will greatly increase the rate of circulation throughthose units above the maximum temperature and willdecrease the timenecessary to lower their temperatures to proper cooling temperature.This will effect substantial savings in the wear of the apparatus andin, the energy required to operate the system as a whole. v

It is thought that the invention and numerous of its attendantadvantages will be understood from theforegoing description and it isobvious that numerouschanges may be made in the form, construction andarrangement of the several parts without departing from the spirit orscope of my invention or sacrificing any of its attendant advantages;the form herein described being a preferred embodiment for thepurpose ofillustrating my invention.

What I claim is: v

1. In a refrigerating system, a base, a casing detachably mounted onsaid base and having a chamber formed therein, alever arranged in saidchamber and pivoted between its ends to said base, an inlet and anoutlet formed in saidcasing and base, respectively, an armature pivotedon one end of said lever, a solenoid fixed in said casing around saidarmature, and a needle valve controlling the flow of liquid throughsaid'outlet, said lever being operable by gravity to hold 2. Inarefrigerating system, a' base, a casing detachably mounted on said baseand having a chamber formed therein, an inlet and an outlet connected tosaid casing and base, respectively,

a valve controlling the now of liquid through a valve controlling theflow of liquid through saiduoutlet, gravity operated means supported bysaid base in said chamber for holding said valve normally open,magnetically operated means controlling the gravity operated means toclose said valve, and means for damping the vibration of the valveoperating means.

- LESTER. U. LARKIN.

